There were complications during the second operation that damaged the pituitary gland and hypothalamus in her brain.

The pituitary gland controls hormonal secretions while the hypothalamus is in charge of emotions and appetite, among other things.

As a result, Bianca must rely on lifelong medication to replace the role of hormones.

The parents also found themselves having to cope with a different Bianca - one with severe mood swings.

One moment, she would be pacing around the house excitedly. Then, without warning, she would throw a tantrum.

"I call her Dr Jekyll and Mr Hyde," Mrs Lai said with a slight smile.

Recently, Bianca became violent and would hit her parents when she is upset.

"She registers tone and body language more than what we say. So whenever she interprets something as negative, she will hit," Mrs Lai said.

During the interview, this reporter saw Bianca strike her parents on their faces with her little palm several times. But Mrs Lai never lost her cool. She would hold her daughter's hands firmly and say: "No, mei mei, it hurts."

Bianca would then cry and kick up a fuss. But a minute later, she would suddenly wrap her arms around her mother, whisper an apology, and then plant a kiss on her cheek.

COPING

Hugging Bianca, Mrs Lai smiled and said: "That's when you know (her hitting) is not malicious."

Mr Lai's way of coping with Bianca's temper is to walk away so he would not aggravate her further.

"She hits me more. The psychiatrist said it could be because I forced her to do what she didn't like," he said.

He had forced his daughter to relearn the use of her right hand after a stroke following the surgery.

"She needed that therapy. It is kind of painful (for me), but if I had to do it all over again, I would still do the same," Mr Lai said.

With Bianca's mood swings, there is rarely a moment of peace at home, except when she is eating.

"Eighty per cent of her frustrations come from the denial of food. Eating is the only time she is quiet, but it's a very small window," said Mrs Lai.

Due to her damaged hypothalamus, Bianca doesn't know when she's full. But the couple don't want to take the easy way out.

"We don't want her to end up with more health problems, like obesity," she said.

The problem is so bad that the kitchen door is locked at all times to prevent Bianca from raiding the fridge, something she has done before.

Taking care of Bianca takes up such a huge chunk of their time and attention that their son once suspected them of favouritism.

"When he was younger, he asked me if I loved Bianca more. That broke my heart. I felt inadequate, I felt I wasn't a good mum," said Mrs Lai.

She also feels sorry for her children for not being able to give them a normal childhood. Family trips are out and there is no extra money or time for recreational activities or extra classes.

"People tell me I'm strong but they don't see my other side. Sometimes I hide in the toilet and cry. There has to be an outlet," she said.

Two years have passed since Bianca's surgery and while the family has learnt to handle Bianca's mood swings better, they still miss the bubbly girl before her surgery.

"My son asked me when the old Bianca was returning. They used to be very close, and she worshipped the ground he stepped on.

"I think I am still mourning the daughter I lost," said Mrs Lai.

All she asks for now is more awareness of brain tumour conditions like Bianca's, and more public understanding.

"When people stare at Bianca, I know the magnanimous thing is to ignore. Inside me, I just want to yell and scream," she said, choking back tears.

"I'm not seeking sympathy. I just hope people would understand her predicament."

Their neighbours even thought the couple were child abusers.

"My helper heard it from my neighbours' helpers. My neighbours thought we were abusing Bianca because of her frequent screams and wails," Mrs Lai said.

"People tell me I'm strong but they don't see my other side. Sometimes I hide in the toilet and cry. There has to be an outlet."

- Mrs Karen Lai on dealing with the pressures of taking care of Bianca

"I call her Dr Jekyll and Mr Hyde."

- Mrs Karen Lai, wistfully describing how Bianca would be happy one moment, and throw a tantrum the next

Benign brain tumours can behave like a cancer

Craniopharyngioma is an uncommon benign brain tumour that has a "high propensity to recur", said Dr David Low, a paediatric neurosurgeon at KK Women's and Children's Hospital.

Out of the 30 to 40 new cases of brain tumours here every year, one or two are craniopharyngioma cases.

The tumour is wedged between the pituitary gland and hypothalamus, and any damage to either part of the brain could result in "fairly devastating side effects", said Dr Low, who is also vice-president of the Brain Tumour Society (Singapore).

Dr Matthew Tung from Pacific Neurosurgery explained that the pituitary gland is responsible for orchestrating hormonal changes in the body. This includes menstruation, sex drive, skin pigmentation and reaction to stress.

"If the pituitary gland is damaged, the patient may have to replace the hormones artificially. It is never as good as the body's ability to control the hormones naturally," he said.

IMPORTANCE

The hypothalamus is important for emotions, motivation, sexuality, consciousness and temperature regulation, Dr Tung said.

"If we damage our hypothalamus, we lose the body's natural mechanism to adjust the body temperature to the surroundings.

"It is also important for growth and appetite in children. It can go either way - an excessive or negative appetite. The effects are unpredictable."

When a brain tumour is benign, it does not mean that it can be left alone, Dr Ivan Ng, a consultant neurosurgeon at Mount Elizabeth Novena Hospital, said.

He explained: "Only cancers kill, but brain tumours are unique in the sense that even though they may be benign, they behave like a cancer - they kill if you don't do anything about them."

Even if the benign tumour is left alone and does not spread, the patient is at risk of losing his vision and hormonal control, he added.